There is a theory, the chaos theory, which suggests a butterfly flapping its wings on one side of the world causes a hurricane on the other through a series of coincidences and ripple effects. The central part of this theory is that everything is connected in some small way, so upset the balance, even in so minor a way as the flap of a butterfly's wing, and the world is irrevocably changed. While there may be no evidence to confirm this fact, there are ways in which we can see how the most ordinary of circumstances can cause vastly different or devastating effects. The wrong word spoken at the wrong time can change a life forever, but then so can the right word. One event, offset when it should have been, can change the world in a way few would expect.

And so, when Midoriya Izuku was born four years later than he would have been in any other universe, the world was changed, though the people in it would never know what it was supposed to be like before. Still quirkless, still trying his best to be a hero anyway, Midoriya Izuku was the anchor point for something bigger than anyone expected of him, the central pillar of a whole generation of heroes. Of course, few people expected anything from a quirkless child. Perhaps this was why he was so determined to prove them wrong.

Izuku knew pain like an old friend. It was a constant in his life, something he encountered every day and somehow, he still managed to get up in the morning and meet it again. Even at age ten, there was a stubbornness down to his very bones, a desperation that pressed at him, demanded he be better and stronger than everything trying to push him down.

He went to school every day and bore the insults and casual aggression of his classmates with a wobbly smile that only seemed to make people angrier. He watched heroes every day, honing his attention to detail by breaking down their quirks, their fighting styles, and their general attitudes. He looked at his classmates with these same eyes, saw the potential to become something better than they were, and stayed quiet even when it hurt.

Kacchan was perhaps the worst offender of those who hurt him, but it didn't stop Izuku from seeing the most potential in him. Explosion was a powerful quirk, useful and rare in the field of heroics. For every burn Kacchan gave him, every scar he didn't earn, Izuku still looked at him and saw the sort of hero he could be.

He was always far better at looking into the future than facing the here and now.

There were times, though, that Izuku let himself feel the pain more deeply, when the words and the actions of his classmates managed to stick in his soul and drive themselves deeper. He had bad days, and he hated that almost everyone seemed to be able to tell when those days were.

It was on one of those bad days that the order of events his late birth had twisted out of joint attempted to reassert itself. Izuku was walking home, ten years old and deeply wounded by Kacchan's cruel words, when a villain made mostly of sludge attempted to kill him.

"Perfect camouflage," the villain muttered. "Just a few minutes and you won't feel a thing."

Izuku fought desperately even as the sludge villain attempted to pour himself down Izuku's throat. He choked and thrashed and felt more pain than he'd ever experienced as his lungs burned for air they weren't getting. Just when he thought he was going to die for sure, he heard familiar words, ones he had heard thousands of times before, but never in person.

"Fear not, kid. I am here!"

All Might stunned the villain with a single punch, the shockwave blasting him apart and Izuku felt himself drop bonelessly to the ground as the darkness set in.

He couldn't have been out for too long because All Might was still there, gently patting his cheek to wake him up.

"Thank goodness," the hero said, leaning over him. "Apologies for getting you caught up in my villain hunt."

"All Might?" Izuku whispered, not quite daring to believe what he was seeing.

"Yes, it is I. And I have captured the villain!" All Might brandished a bottle filled with sludge. There were a couple of eyes floating in it, the same eyes that Izuku had seen hovering over him malevolently before the villain attacked. "And now I must be on my way."

"Wait, please!"

All Might was already leaving though, and Izuku desperately latched onto his leg hoping to stop him. In hindsight, this was an unbelievably bad plan, but he didn't know what else to do and this was his only chance to ask his hero an important question.

All Might didn't realize he was there until they were high in the air and Izuku would fall to his death if he let go. They landed atop a building more than a mile away. The man wouldn't even look at him, and Izuku couldn't really look at him either. He stared at the ground, desperate and suddenly afraid in a way he had never been before.

"Can someone without a quirk become a hero like you?" he asked, not daring to look up. "Could I do it even if I don't have a quirk?"

A quiet sound, like rushing steam or escaping air drew his eyes up again and he looked at the place where All Might had been, only to see a strange skeletal man standing there.

"Damn it," the man muttered. "I ran out of time."

Izuku's mind, for the first time in his life, went suddenly, terrifyingly blank as he tried and failed to process the sight in front of him. Where All Might had been, there was a strange man who looked half-dead, wearing the same clothes All Might had been wearing a moment ago, but hanging loosely off him.

"What?" was the most intelligent response he could form. "What?"

The skeletal man sighed, blood dripping down his chin. "Now you've seen my true form. Don't go writing about it on the internet."

"You're All Might? But how-?"

"It wasn't always like this, kid. I mean, there was a bit of a transformation aspect to it, but it was more like this after I got hurt five years ago." All Might lifted up his shirt to show Izuku a large puckered scar that took up most of the left side of his chest, the center of it just barely too low to have hit his heart. "Now I can only keep up my power for three hours per day."

"Five years ago? The fight against Toxic Chainsaw?" Izuku frowned. He remembered that fight, and he couldn't remember All Might taking a significant hit at all.

"No, not him. This one-this fight wasn't made public. When you're the symbol of peace, it can be more damaging to let people see you almost defeated. And I was. I beat him in the end, but this was the cost." All Might put his shirt down and looked at Izuku. "You want to be a hero, and that's an admirable thing, but it's dangerous. Too dangerous for someone without a quirk. There are other options out there to help. The police help people all the time, and it's much safer to do that than to do what I do."

The man stood up even as Izuku could feel the world crumbling out from under him because his hero didn't think he could be a hero too. The words hit different than anyone else's had, even Kacchan's. A part of his soul was shattering and Izuku was helpless to figure out how to keep it together.

"Wanting to be a hero is great," All Might continued as he made his way to the door leading downstairs. "But at some point, you also need to be realistic."

Izuku sat there for a while, the pain thrumming in his chest alongside his heartbeat. He waited until he was sure All Might was gone before going down the stairs.

"Just one person," he muttered to himself, looking at the notebook Kacchan had practically destroyed earlier that day. Hero Analysis for the Future #7. It had All Might's signature in it, but he couldn't bring himself to open it up to that page. "Is it too much to ask that one person believe I can be a hero?"

The sound of explosions drew his attention to a crowd gathered around yet another villain battle. In spite of himself, Izuku wandered over to see what was going on, more out of habit than any actual desire to analyze any of the quirks being used.

Over the heads of the crowd, swirling bits of sludge thrashed back and forth, almost in tune with the explosions. It was familiar and wrong and Izuku knew with a deep sense of dread that this was his fault. Worst of all, he knew exactly who the explosions were coming from.

"Kacchan."

Something sick settled in the pit of his stomach as he pushed his way through the crowd to the front of the line. People were talking and staring, several heroes were standing nearby trying to contain the damage, but no one was trying to save Kacchan.

Your fault, the words beat a rhythm in his head. Your fault.

"Someone will help," Izuku whispered to himself. "Someone has to."

Seconds were ticking by, endlessly long but no one was trying to help Kacchan. His explosions were tapering off, a sign of over-exertion or something else, Izuku couldn't be sure, but he was afraid of what it might mean. He saw the fear in Kacchan's eyes, and it was wrong. He shouldn't be afraid. Kacchan wasn't afraid of anything.

Your fault.

Izuku's legs were moving before he knew what was happening. His notebook dropped out of his hands somewhere along the way as he took his backpack off his back and threw it at the villain's eyes, the only part of him that wasn't sludge.

It was enough to give Kacchan the space to breathe. He reached into the sludge desperately, trying to pull him out and away, but the sludge was still fighting. A large hand closed over their arms and yanked them away as All Might punched the ground with one of his signature moves. For the second time that day, the sludge villain was blasted away in pieces by the shockwave.

Your fault.

Izuku bore the lectures from the other heroes on the scene because he knew he deserved it. It was his fault Kacchan was even put in that position. He didn't regret running in though. He wouldn't have regretted it even if he had died if it meant that Kacchan was safe. He picked up his bag and his notebook and left the scene.

"Deku!"

Izuku jumped and turned to look at Kacchan, who stood there tense and angry, tiny explosions flicking off his knuckles.

"I never asked you to save me! As if you could! I could have beaten him myself!"

For a moment, Izuku couldn't help but stare at the boy who had been his best friend as a child. He was as angry as he always seemed to be, if not a little more so because of everything that had happened, but there was still a sort of deep relief in his eyes and an edge of fear that hadn't gone away.

"How dare a quirkless failure like you pity me! Trying to win me over? Don't you dare mock me, you stupid nerd!" And with that, Kacchan swiveled on his heel and stalked away.

"Just one person," Izuku whispered, staring down at his hands.

He started for home, the constant echo of your fault humming in his ears. But he stopped at the bottom of the stairs leading up to his apartment, a sudden realization coming over him like a bolt of lightning.

"I'm one person."

They had so many discussions about self-esteem in school. He'd been given more than a few of them by the school counselor, who seemed to think that the majority of his class being against him was because he wasn't confident enough in himself, nevermind his classmates actively attacked any confidence he ever tried to develop. But one of the most common things that came up in those lectures was that if he wanted other people to love him, he needed to start loving himself.

Nobody believed that he could be a hero. Not even him, in spite of how loudly he declared his big dreams to the world. That's why he'd asked All Might, hoping he might see something in him worth calling him a hero. But he hadn't, and Izuku wondered if that was because he couldn't see himself as a hero yet. If he couldn't believe in his dream, why should anyone else?

He walked into the apartment, offering the customary greeting to his mother and went to his room, still trying to wrap his head around this realization. He only wanted one person to believe in his dream of being a hero, and he was one person.

It was startling to know now that he hadn't even believed in himself. All of his drive and determination to prove people wrong, to prove that he could be a hero without a quirk, and he was still looking for that validation somewhere else because he didn't even think himself capable of it.

All Might didn't think he was capable of it. All Might had told him to be realistic. All Might had suggested he become a police officer.

But he didn't want to be a police officer. He wanted to be a hero.

An old part of him was waking up, so old he hardly remembered the belief that had filled him to his core. He remembered being a child before he was sitting in a doctor's office listening to the most traumatic diagnosis of his life. He remembered what Kacchan was like then, how they swore they would be heroes together.

Kacchan had believed in him before, had believed in both of them, but he'd left that all behind. Izuku had too, in a way. The doctor saying he was quirkless had broken him more than he expected, had stolen the belief in his dream and convinced him that it was impossible.

Izuku wanted to believe in himself again. He wanted to wake up every day and know that he had an achievable goal in mind.

"The most important thing about big goals is to break them down into something smaller. If you want to do something you think is impossible, figure out all the steps to take to make it possible."

The teachers hadn't really been talking to him. They didn't believe in his dreams either, but they had told everyone how to make goals, how to break them up into smaller goals, things that were much more achievable than throwing themselves into something that would take a long time to see any sort of results.

He broke down quirks all the time. Why shouldn't he be able to do the same thing with his goals?

Izuku reached for a new notebook and wrote 'Achievable Goals' across the front. He turned to the first page and started writing.

Things didn't get better overnight. There was no reason they would, and by the cold light of morning, Izuku stared down at the goals notebook with more than a little bit of doubt

He had no more than a page or two written and there were a lot of things scribbled out or shifted around or, in the case of one particular bit, ripped out. As it turned out, breaking down a goal was a lot harder than breaking down a quirk because at least with quirks he understood where they came from and how certain types of quirks operated. The end goal of 'become a hero' had to have a lot of steps in it, but he didn't know what those steps were. Getting into UA or another high school like that would improve his chances at his end goal, but most hero schools didn't even accept quirkless kids in the general education department.

He turned back to his hero analysis notebooks. After grimacing at the signature of All Might spread across a couple of pages, he put them together with a paper clip so he wouldn't have to see it every time he opened notebook #7. On the next blank page, he started a list of heroes who exhibited skills not related to their quirks. If he could prove that heroes fought with more than just their quirks, he might have a place to start, especially if he could identify what sort of skills they knew.

The list was surprisingly long. All quirks were useful, but not all were useful for the same things, and even when the heroes specialized in certain areas like rescue operations or villain capture, their quirk wasn't the only thing they used.

Strength was important. This was clear from the number of strength enhancement quirks on the hero and villain scene. Even All Might had some sort of strength enhancement quirk, as he'd discovered, but that strength alone wasn't enough. So, strength and the knowledge of how to use it in a fight. That was something he could figure out.

Where people didn't have strength, they used speed. Most people with speed quirks weren't likely to get into direct battles with villains, and they used their speed to pull sneaky attacks or set up traps. So, there was some sort of strategy that needed to be applied alongside speed, especially if you were facing someone you couldn't defeat directly. Which, in Izuku's case, would be probably everyone.

Heroes with elemental quirks relied heavily upon their abilities, but that didn't mean they didn't know how to fight. A lot of elemental quirks relied on distance, and their tactics changed the closer they were to everything. Only Endeavor seemed of the opinion that fire from a distance and fire up close was an excellent strategy in a fight and wreathed himself in his flames. A perk of being fire-proof, no doubt. But that brought up the need for Izuku to find something that could be just as long-range as an elemental attack. Any villain with such an ability would be fighting to keep him from getting close where their abilities would be more difficult to control, so having a distance ability of some sort would be vital.

As he was going through his notes, a creeping realization stole over him. The heroes who had been standing around when Kacchan was being attacked hadn't done anything because their quirks weren't a good match for the situation. They were waiting for someone else to come. At first, so had Izuku. Kacchan had almost died because the heroes couldn't adapt to a situation that didn't suit their quirk. Only Izuku, who had looked at the situation as it was, seen how the villain's eyes were solid, had seen there was a weakness worthy of exploiting there. And he had exploited it. All Might might have ultimately saved the day, but Kacchan might not have survived if Izuku hadn't done something.

It was a small thing, now, to know that his faith in heroes had been shaken. Their quirks were wonderful, he still thought that, but they weren't everything. The best heroes knew how to adapt their quirk or themselves to a less than ideal situation. On the surface, everything All Might did relates back to punching and fighting, and so does Death Arms. But Death Arms couldn't-or perhaps just didn't-punch the sludge villain into submission. All Might used the shock wave caused by the punch in both cases to take the villain down. He adapted to a situation his quirk wasn't really suited for, and he won.

Staring at the notes he had made and the connections that were slowly starting to fill in, Izuku wondered for the first time if his quirklessness wasn't actually the burden he had been led to believe it was. Without the power to back up his intentions, he would have to fight smarter and harder than anyone else. He would have to adapt to any situation to get through. Maybe without a quirk he could be the single most versatile hero the community had ever seen.

He wondered why no one had thought of this before.

Picking up his goals notebook again, he opened it up to a fresh page and wrote: learn to fight (martial arts?), find books on strategy and tactics, start exercising.

They were simple places to start, but Izuku felt like it was progress, and he certainly wasn't going to beat himself up over progress.

"Mom," he called, getting dressed in something he wasn't afraid to get sweaty and terrible. "I'm going to go out for a run."

Yagi Toshinori limped his way toward Sir Nighteye's agency. They hadn't really been on speaking terms lately and Toshinori regretted that. He had been stubborn and hard-headed and unwilling to compromise on anything and if it hadn't been for that kid, he might have continued doing what he was doing until he died the way Mirai expected him to.

But Toshinori was starting to remember why he had become a hero in the first place, and it makes him want to thank the kid. It wasn't for the image or the fame; it was because he genuinely wanted to help people wherever and whenever he could. The fact of the matter was, however, that his time was running short and he didn't have forever to wait. If he managed to die with One for All, the power would be lost and All for One would have won in the end. Even if the man was dead, that sort of power was meant to stay in the world. It's meant to help.

So, he decided to abandon his silly pride and talk to his former sidekick again. Mirai was always more concerned with the future, always looking for ways to change it, to make it better. He'd said Toshinori would die if he didn't find a successor, that he needed to pass on the power before that happened and Toshinori was starting to agree with him now. Heroes were meant to keep people safe, and he wasn't keeping anyone safe holding on to One for All like that.

Maybe this was the way it was supposed to be anyway. Mirai was the one who could look into someone's future after all. Toshinori just wished he'd managed to see who he should give it to. That would make things a lot easier.

He stepped up to the reception desk. A bored young woman was sitting behind it. Sir Nighteye's agency wasn't the busiest of places, especially on the public floor. Toshinori knew that most of the activity was confined to the upper floors, where research and training and investigating happened throughout the day and night. The reception area was more a formality than anything else, a place where outsiders went to make appointments to consult with Mirai or offer up a particularly difficult case.

"Do you have an appointment?" she asked, a hint of detached professionalism attempting to cover her apathy.

"Ah, no." Toshinori said, thinking that perhaps he should have called ahead or something. "But I hoped I might speak to Sir Nighteye if he's available."

"Name?"

"Yagi Toshinori."

The woman didn't sigh, but Toshinori thought it was a near thing. If he had to guess, the appeal of the job is that she didn't have to do much more than field calls. Though she seemed to be slightly averse to even that little bit of effort. Honestly, he hoped her job was temporary, as he didn't want to think about how damaging this sort of reception could be for the agency.

She picked up her desk phone and dialed the extension for Mirai's office. He could hear it ringing on the other end before a voice, low enough that Toshinori couldn't make out words, answered.

"There's a Yagi Toshinori here at the desk," she reported. "He says he wants to speak with you."

She blinked faintly, a touch of surprise on her features as the answer, likely an affirmative, was given.

"Yes, sir." She hung up the phone and looked at him. "He says to go on up to his office. Sixth floor. Down the hall to the right."

"Thank you," he said with a slight bow. Because even if she wasn't very polite to him, he had a duty to be polite himself.

He didn't tell her that he remembered the way from when Mirai first opened the agency, and he didn't admit to knowing Mirai at all personally because he honestly didn't think she'd care. That, or she'd assume he was trying to impress her.

He doubted anything could impress that woman.

The elevator arrived almost too soon to the sixth floor and Toshinori had to recollect his thoughts, which have somehow scattered in the time it took him to make his journey. The core of it was the same, but he couldn't really explain everything as it sat in his head.

Suddenly he was standing in front of Mirai's office door and his thoughts, hastily collected, had scattered again. He lifted a hand, marveling again at how sharp and bony they had become in the intervening years since he was last here, and knocked.

The door was flung open and Mirai was standing there, fear and desperation and hope flickering across his normally controlled face.

"You're-" Mirai pulled himself up short, abandoning what he'd been about to say with no small amount of effort. Toshinori wondered if it might have been about the fact that they seem to be the same height now. Instead, he stepped back, opening the door wider. "Please come in."

He did and reached quickly for a handkerchief to wipe away the blood he coughed up when he caught sight of the All Might memorabilia filling the space.

"Been busy, I see," he teased, and something that was almost a blush appeared in Mirai's cheeks.

"I was keeping an eye on you." As if that explained the limited-edition poster hanging prominently on one wall. "What brought you here today?"

Toshinori sighed. He wasn't looking forward to this conversation, but Mirai had the right to forge straight ahead into it. "I wanted to say that I was sorry for all of the things I said before. I was wrong and more than a bit selfish, I think. Being a hero is the only thing in my life I wanted, and by then it was the only thing that made sense. But I know I can't keep doing this forever. Already I'm having trouble helping when I'm needed. I need to find a successor, someone who can take One for All and keep going forward."

"Why now? What changed your mind?" Of course, Mirai could see straight to the heart of things and start digging for all of his answers.

"I met a child today, a boy who reminded me why I became a hero in the first place." And it only struck him then that he didn't know the kid's name. The boy had thrown himself into Toshinori's life like a hurricane, upsetting all of the things he thought were true about him and what he did, and he didn't even know the boy's name. "He's quirkless, but he wants to be a hero. And when his friend was in trouble, he ran in without thinking and tried to help. I had to help, of course I did, but he reminded me of myself and the things I wanted when I was growing up."

"Because you were quirkless and your mentor gave you One for All." At least that was one thing he didn't have to explain. Mirai was one of the few people he had told the full story to. "Why do you want my help? Why not give it to this boy who reminds you so much of yourself?"

"Because he's in elementary school. One for All could destroy him if he tried to use it. He's much too young, and I don't think we can wait until he's old enough to try."

Mirai nodded. "All right. I have a couple people in mind, but you probably want to meet them first."

"I would prefer to, yes."

"Then I'll see what I can do. Is your phone number still the same?"

Toshinori took out his phone. "Yes. And I still have your number as well."

Something softened in Mirai's face, as though he had expected Toshinori to have deleted it after their fight and was touched that he hadn't. "Good. I'll let you know when a good time would be to meet with them. And thank you."

"For what?"

"For coming back."

In that moment, Toshinori saw how deeply the separation had affected them both. He had tried to ignore it and run away from it, but it had still hurt that he couldn't talk to his former sidekick. He had fled Japan after that, spending more time in the United States than in his home country so he didn't have to be reminded of all he was avoiding. Mirai had hurt for that separation too, watching from a distance when all he clearly wanted to do was mend that bridge and prepare everything against the future.

Toshinori offered him a weak smile. "I think I always would have, but that boy made me realize that things needed to change. So, you should be thanking him."

Mirai smiled back. "If I meet him, I will."

Thanks for reading! I hope you have enjoyed and choose to leave a comment. To my readers from Can't See The Forest For The Trees, sorry for the lack of update over there, but the next chapter isn't complete and my muse has been splitting time between about ten different projects, this being one of them. Hopefully you enjoy this one as well. And to those who aren't into genderbent characters, hi and welcome. Canon genders apply here, so no worries (and hopefully no complaints).